GE 339

CHAPTER 6: SETPOINTS S3 PROTECTION
339 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL 6–87
Figure 6-37: Underfrequency logic diagram
SETTING
UNDRFREQ FUNC Disabled = 0
Latched Alarm Alarm
Trip
SETTING
BLOCK 1: Off = 0 BLOCK 2: Off = 0 BLOCK 3: Off = 0
UNDRFREQ ALARM PKP
S R
LATCH
LOGIC OPERAND
UNDRFREQ ALARM OP
LOGIC OPERAND
OR
OR
AND
AND
AND
AND
OR
AND
AND
INPUTS
Emergency Restart Input Lockout Reset Input
SETTINGS
Off = 0 Lockout Reset Off = 0
Emergency Restart
S4 CONTROLS
UNDRFREQ State: Operate
Alarm
TARGET MESSAGE
ANY ALARM OP
UNDRFREQ TRIP OP
ANY TRIP OP
S R
LATCH
UNDRFREQ Trip State: Operate
TARGET MESSAGE
ANY ALARM PKP UNDRFREQ TRIP PKP ANY TRIP PKP
AND AND
OR
S3 UNDERFREQUENCY
S3 UNDERFREQUENCY
OR
Reset Input
Reset Off = 0
AND
OR
KEYPAD RESET
ANY LATCHED ALARM OP
UNDRFREQ State: Pickup
Alarm
TARGET MESSAGE
UNDRFREQ State: Pickup
Trip
S3 UNDERFREQUENCY
Vab
UNDRFREQ PICKUP:
RUN
Van
f < PICKUP
DeltaWye
896833A1.cdr
SETTING
Phase Voltage Inputs (associated setpoints)
SETTING
UNDRFREQ DELAY
t
PKP
S3 UNDERFREQUENCY
Frequency Measurement
Wye-connected VT: Van Delta-connected VT: Vab
SETTING
MIN VOLTAGE
Van > Minimum
S3 UNDERFREQUENCY
f = 0
OUTPUT RELAY X
SETTING
Do Not Operate, Operate